Cladorhizidae (Porifera, Demospongiae, Poecilosclerida) of the deep Atlantic collected during Ifremer cruises, with a biogeographic overview of the Atlantic species
Résumé
The study presents Cladorhizidae collected during Ifremer cruises in the Atlantic Ocean from 1981 to 2004. Fifteen species are described from the genera Abyssocladia, Asbestopluma, Chondrocladia and Cladorhiza, with complete descriptions of five new species. While a couple of species were collected at 670-1010 m depth at the Rockall Bank, most species were collected at middle to lower bathyal and abyssal depths (similar to 2000-5000 m), ranging from the northern Atlantic to the Mid-Atlantic Ridge and the coast of Africa at Gabon-Congo. A biogeographic analysis of currently known Arctic, Atlantic and some Antarctic species shows that the majority of included cladorhizids are described from the north-east Atlantic and Arctic Oceans while a lower number of species are known from other parts of the Atlantic Ocean. Large regions are poorly investigated, and previously undescribed species can be expected when sampling in these areas. A regional mostly endemic cladorhizid fauna is predicted for shelf and upper slope areas. Species in the lower bathyal and abyssal seem on the other hand to have a wider geographical distribution.